Generally, a line blind valve is provided at a boundary of a hydrostatic tester of the piping to block and open the fluid flow in the piping. In the case of connecting pipes, in which different types of fluids flow, it is provided to prevent the fluids from being introduced to each other or to prevent the fluids from being mixed with each other.
A conventional blind valve, as shown in FIG. 1 is a valve installed between pipes to open or block a pipeline, and includes: a valve body 10 having opening portions 11 and 12 formed at front and rear sides thereof, respectively; a front sheet 15 formed from the opening portion 11 of the front side toward an inside of the valve body 10, and a rear sheet 16 formed from the opening portion 12 of the rear side toward the inside of the valve body 10; a blind plate 20 being provided between the front sheet 15 and the rear sheet 16 and including an opening member 21 formed with an opening to open the pipeline, and a blocking member 22 provided at an upper portion of the opening member 21 to block the pipeline; a moving shaft rotating by being geared to a surface of the blind plate 20 to move the blind plate 20 up and down, thereby opening and blocking the pipeline; and a gear unit 40 configured such that a ring gear 41 engaged with the rear sheet 16 moves forward to press a ring sheet 42, whereby the ring sheet 42 presses the blind plate 20 toward the front sheet 15 to sealingly fix the same.
Here, to bring the blind plate 20 into close contact with the valve body 10, the gear unit 40 is operated such that the ring sheet 42 pushes the blind plate 20 toward the front sheet 15, which requires a complicated structure, so manufacturing cost is high due to a variety of components, and the blind plate is sealed with a complicated structure.
Herein, the ring sheet 42 should come into close contact with not only the blind plate 20 but also the rear sheet 16, and the ring sheet is configured to move to an outer circumferential surface of the rear sheet such that mutual sealing is ensured, thereby resulting in complexity of coupling and configuration.
Accordingly, it is necessary to develop a blind valve that can solve the above problems.